From cd968863c25c09ffc83c51e7e673b1059d4f9501 Mon Sep 17 00:00:00 2001
From: Klemen Oslaj <klemenoslaj0@gmail.com>
Date: Sat, 21 Mar 2020 06:07:29 +0100
Subject: [PATCH] fix(cdk/coercion): add the support for readonly array
 coercion (#18807)

Fixes a type definition of coerceArray so that it accepts both mutable and
immutable arrays.

Fixes #18806
---
 src/cdk/coercion/array.ts                | 2 ++
 tools/public_api_guard/cdk/coercion.d.ts | 1 +
 2 files changed, 3 insertions(+)

diff --git a/src/cdk/coercion/array.ts b/src/cdk/coercion/array.ts
index 6ab9c7eb1d4b..d76caf60ccde 100644
--- a/src/cdk/coercion/array.ts
+++ b/src/cdk/coercion/array.ts
@@ -7,6 +7,8 @@
  */
 
 /** Wraps the provided value in an array, unless the provided value is an array. */
+export function coerceArray<T>(value: T | T[]): T[];
+export function coerceArray<T>(value: T | readonly T[]): readonly T[];
 export function coerceArray<T>(value: T | T[]): T[] {
   return Array.isArray(value) ? value : [value];
 }
diff --git a/tools/public_api_guard/cdk/coercion.d.ts b/tools/public_api_guard/cdk/coercion.d.ts
index 1cf0d8e786ec..72cc86a324bb 100644
--- a/tools/public_api_guard/cdk/coercion.d.ts
+++ b/tools/public_api_guard/cdk/coercion.d.ts
@@ -3,6 +3,7 @@ export declare function _isNumberValue(value: any): boolean;
 export declare type BooleanInput = string | boolean | null | undefined;
 
 export declare function coerceArray<T>(value: T | T[]): T[];
+export declare function coerceArray<T>(value: T | readonly T[]): readonly T[];
 
 export declare function coerceBooleanProperty(value: any): boolean;